class_docstr: Default namedtuple describing `Graphs`s.
  
  A children of `collections.namedtuple`s, which allows it to be directly input
  and output from `tensorflow.Session.run()` calls.
  
  An instance of this class can be constructed as
  ```
  GraphsTuple(nodes=nodes,
              edges=edges,
              globals=globals,
              receivers=receivers,
              senders=senders,
              n_node=n_node,
              n_edge=n_edge)
  ```
  where `nodes`, `edges`, `globals`, `receivers`, `senders`, `n_node` and
  `n_edge` are arbitrary, but are typically numpy arrays, tensors, or `None`;
  see module's documentation for a more detailed description of which fields
  can be left `None`.
docstr: Asserts that the set of `None` fields in the instance is valid.
docstr_tok: ["Asserts","that","the","set","of","`","None","`","fields","in","the","instance","is","valid","."]
code: def _validate_none_fields(self):
      """Asserts that the set of `None` fields in the instance is valid."""
      if self.n_node is None:
          raise ValueError("Field `n_node` cannot be None")
      if self.n_edge is None:
          raise ValueError("Field `n_edge` cannot be None")
      if self.receivers is None and self.senders is not None:
          raise ValueError(
              "Field `senders` must be None as field `receivers` is None"
          )
      if self.senders is None and self.receivers is not None:
          raise ValueError(
              "Field `receivers` must be None as field `senders` is None"
          )
      if self.receivers is None and self.edges is not None:
          raise ValueError(
              "Field `edges` must be None as field `receivers` and `senders` are "
              "None"
          )
  
file_path: graph_nets/graph_nets/graphs.py
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  import collections
label_desc: Use image node_id 1 for calling the GraphsTuple obj's underlying member method code with example usage: obj._validate_none_fields() without return types